超声辅助H2O2-CH3COOH脱除宁东煤中硫分和灰分研究

选取宁夏宁东两种煤样ND1和ND2作为研究对象,在超声频率为40 kHz,功率为800 W下,以H2O2-CH3COOH为助剂,分别超声作用5 min,10 min,20 min,30 min,40 min,50 min,60 min和120 min。对超声作用前后的煤样进行化学法形态硫分析、FTIR、XPS、BET、XRD和IC分析。结果表明:随着超声作用时间的延长,全硫脱除率逐渐变大,超声作用60 min后再延长时间,全硫含量变化较小。当超声作用60 min时,ND1和ND2的最大全硫脱除率分别为44.05%和55.33%,硫铁矿硫的最大脱除率分别为34.62%和51.52%,硫酸盐硫的最大脱除率分别为58.33%和57.14%,有机硫的最大脱除率分别29.06%和48.04%;超声处理后样品中含氧官能团含量增加,低价态硫向高价态转化,硫可以被氧化为硫酸根而被脱除;超声处理后样品孔径和比表面积变大,改善了固液接触效果;超声能脱除煤中的矿物质,ND1和ND2中的灰分分别由24.25%和13.96%下降至7.65%和10.98%,最大脱灰率分别为68.45%和21.34%。

Desulfurization and Demineralization of Ningdong Coal via Ultrasonic- assisted in H2O2-CH3COOH System

ND1 and ND2 coals in Ningxia Ningdong were selected as raw meterial. The ultrasonic frequency was set as 40 kHz with the power as 800 W, and H2O2-CH3COOH was used as an auxiliary agent. The reaction time was 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min and 120 min. The coal samples before and after the ultrasonic treatment were analyzed by using the wet chemical analysis, FTIR, XPS, BET, XRD and IC analysis. The results show that with the increasing ultrasonic time, the total sulfur removal rate increases gradually. When the ultrasonic treatment takes more than 60 min, the total sulfur content slightly changes. When the 60 min-ultrasonic treatment is used, the maximum total sulfur removal rates of ND1 and ND2 are 44.05% and 55.33%, respectively;the maximum removal rates of pyrite are 34.62% and 51.52%, respectively;the maximum removal rate of sulfate sulfur are 58.33% and 57.14%;and the maximum removal rate of organic sulfur are 29.06% and 48.04%, respectively. After the ultrasonic treatment, the content of oxygen-containing functional groups in coals increases, the low-valence states of sulfur are converted to high-valence states, and sulfur are oxidized to sulfate and removed. The pore diameter and specific surface area increase, which improves the solid-liquid contact effect. Therefore, the ultrasonic treatment can remove the minerals in the coal. Specifically, the ash in ND1 and ND2 decreases from 24.25% and 13.96% to 7.65% and 10.98%, respectively, and the maximum demineralized rate are 68.45% and 21.34%, respectively.